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a formality with the cops, a sort of hazing I had to navigate before being embraced as a fellow hero. Things didn’t work out the way I’d hoped, and only after I was branded a liar and rejected did I really begin thinking about this weird thing, the polygraph, and why law enforcement depends on it. What strikes me now is how legitimate it all seemed. The office of the polygraph examiner didn’t look like a traveling gypsy sideshow. The examiner wasn’t wearing purple robes and a conical hat. In a desolate little business park, Boyd, Smith & Associates was the door with bars on it. Inside was a white lobby with old magazines and plastic plants on the tables, and various diplomas posted on otherwise barren walls. Sidney Smith was a stout, white-bearded old fellow in a plaid shirt who greeted me vigorously, as though we were old friends. I was soon signing a form, acknowledging him to be “a professional polygraph examiner, who is licensed by the State of Texas Polygraph Examiners Board.” No similar board exists in Texas for the licensing of witches or warlocks or voodoo palm readers. The Occupations Code does regulate “persons who purport to be able to detect deception,” but only those who purport to do so “through the use of instrumentation:’ Such persons must meet “minimum instrumentation requirements” by going to a board-approved lie-detecting school \(such as the Texas Department of Public their prowess before the board of examiners. Since most board members are polygraph examiners, they claim to know a true lie detector from “untrained, unlicensed and unscrupulous” fakers. Sidney Smith’s license was proof that I was getting the real thing. I followed him down a dark passage and emerged in another stark room. Beside a white wall was a large chair and, behind the chair, a desk with a machine on it. The machine seemed to have plenty of wires; instead of the old-style paper scroll, there was a glowing computer monitor. It looked even more scientific than the polygraph machines I remembered from TV, and I suppose I thought that you probably have to be highly skilled to operate such a machine. Together, he and his polygraph must produce reliable results, I assumed, or the state of Texas would not have licensed Smith, and the Houston police would not have sent me here. Only later did I realize how stupid I was. In the most authoritative study yet done, a committee appointed by the National Research Councilthe Committee to Review the Scientific Evidence on the Polygraphfound that a polygraph exam is administered today much as it was 90 years ago, when the machine was invented by the creator of Wonder Woman, William Moulton Marston. “The theoretical rationale for the polygraph is quite weak,” the scientists sniffed. You don’t have to look hard to see the problem: The lie detector doesn’t detect lies. The machine merely graphs fluctuations in sweat, blood pressure, and heart and respiration rates while the subject is examined. All else is Only after I was branded a liar and rejected did I really begin thinking about this weird thing, the polygraph, and why law enforcement depends on it. left to the examiner, and “one cannot rule out,” the scientists wrote, “the possibility that polygraph responses vary systematically with characteristics of examiners, examinees, the test situation, the interview process, and so forth:’ An even greater fault exists in the standardized aspects of the testnamely, the assumptions on which an examiner bases his judgments. “Theory,” the committee’s scientists observed, “invokes the following presumed chain of mechanisms”: that lying makes people anxious; that people exhibit their anxiety physically; that the polygraph records these physical symptoms; and that a show of anxiety on a polygraph chart is thus the sign of a lie. “The validity of psychophysiological detection of deception by the polygraph depends on validity all along this chain,” the scientists wrote. And “important threats to construct validity come from the fact that the physiological correlates of psychological arousal vary considerably across individuals, from the lack of scientific evidence to support the claim that deception has a consistent psychological significance for all individuals, and [not least] from the fact that psychological arousal is associated with states other than deception.” In other words, not everyone gets anxious when they lie, and not all anxious people are liars. Only the examiners assume otherwise, and perhaps the strangest aspect of their strange science is that they depend on subjects to lie. In the test’s most common form, the examiner selects certain questions “to create a temptation to deceive,” the scientists noted. Negative answers to such questions as “Have you ever violated a minor traffic law?” are presumed to be lies. And whether you lie or not, you pass the test by showing stronger physiological symptoms of anxiety during these “probable lie questions” about minor traffic violations than to queries regarding your possible involvement in bestiality or incest or murder. The review committee ultimately found “little basis for the expectation that a polygraph test could have extremely high accuracy.” The best they could say was that in controlled tests regarding specific events \(such as, “Did you rob the bank the many easy ways to thwart the test, the polygraph might discriminate lying from truth-telling at rates better than chance. When the polygraph is used in employment screening, accuracy is “almost certainly lower,” the committee reported, because questions such as “Have you ever committed a crime?” are so open-ended that “two examinees who have committed MARCH 20, 2009 THE TEXAS OBSERVER 11